1. Field
Embodiments of the present invention relate to an electronic device equipped with a hinge mechanism that allows positioning of a display panel in such ways that in one case a display screen is facing down on a main body and in another case the display screen is laying face up away from the main body.
2. Description of the Related Art
Currently, there are portable electronic devices that allow rotation of the display panel by 180 degrees with respect to the main body. In this type of the electronic device, there is a possibility of damaging the hinge portion when the display panel is rotated inadvertently more than 180 degrees.
In order to mitigate the possibility of damage, these electronic devices display an image, on a portion of the display screen, indicating the allowed rotational direction from the current state. However, in such electronic devices, built-in sensors and switches are required around the hinge to detect the rotational position. In addition, there is a need for a built-in control function to display the rotational direction that would operate in conjunction with the sensors and switches. When sensors and switches are incorporated into the hinge assembly, the hinge assembly becomes very complex and its production cost will increase.
Also, in such electronic device mentioned above, the allowed rotational direction of the display panel cannot be known unless the display device is activated. If the display panel is very small as in the case of a portable phone, the point of applied force and the action point are very close to the hinge mechanism. Therefore, the torque applied to the hinge mechanism is very small even if the user rotates the display panel in the wrong direction, and the possibility of damaging the hinge mechanism is very small.
However, when the display panel is larger, the rotational resistance of the hinge mechanism is purposely set higher so that the display panel does not rotate unintentionally due to its own weight. Because of this high rotational resistance setting, the user, when trying to rotate the display panel, may have a difficult time determining whether the panel is difficult to rotate because of the high resistance setting of the hinge mechanism or whether he is attempting to rotate the panel in the wrong mechanical direction.
In this case, unless there is a rotational direction indicator, the user may try to rotate the panel in both directions in order to find out which way the panel may rotate. When the panel size gets larger, the point of the applied force and the action point get farther away from the hinge mechanism. As a result, even if a small force is used to rotate the panel in the wrong mechanical direction, a large force is applied to the hinge mechanism, and there is a danger of damaging the hinge mechanism.